Member postings for norm norton

Ahh.. Thank you Martin and Andrew - got that.

So I (and perhaps two others in the world) have been misunderstanding the output from the workshop VFDs that we use. It is 240v phase-to-phase, and if there was a neutral it would be about 133v on each phase to neutral.

I guess the rules of physics say that one cannot phase shift 240v AC by 120 degrees and again by another 120 degrees, otherwise we would get 415v quite easily.

Norm

I thought I had a limited understanding of this, but now I am confused.

If a residential road is fed with three separate phases of 240v, then each house takes a feed from one of those phases and has single phase 240v. If an industrial premise takes all three phases then (I assumed) it has an available feed of 415v (or 380v or whatever) 3 phase. Correct or wrong?

Or are there transformers on the old poles to drop 415v lines down to 240v domestic?

Now if you take one of the 250v phases, and put it through a VFD box, is the output actually three separate 250v sine waves each shifted by one-third of a cycle. If so, why is this phase adjusted supply not producing 415/380v 3 phase?

I need to see the actual AC diagrams perhaps of the two 3 phase scenarios I have described. I think Gerard was asking the same question.

Norm

Hi Andrew

I think I can visualise what you are saying, as I guess you have the centrifugal bob weight set up for a classic British twin. The first thing I would suggest is that the bike is going to run a lot better if you fitted an electronic ignition like a Pazon or Boyer. However, if you want to keep things as they are and not spend too much then I understand you are looking for a simple fix.

I am going to be more simplistic than the previous contributor's good engineering suggestions. The bob weights are always very sloppy on the pins, and tend to go from full retard to full advance in a sudden jump anyway. Precise engineering is not essential. Why don't you fix a solid bush made from bronze or even cast iron into the bob weight hole with loctite. You could custom shape the insert by hand filing to match any worn hole shape. The loctite will fill gaps if you make the shaped insert a press fit in. Then drill a hole, in the right place, that just fits over the existing worn pin. You could dress the pin by hand if it is very mis-shapen or tapered. Use a long, thin strip of emery to work it round and smooth. Hopefully it will still be big enough to do its job of holding onto the bob weight.

Maybe nearer to bodge-engineering than precision but it is always possible to over-engineer a repair job.

Norm

Edited By norm norton on 08/01/2020 10:12:04

Thank you for the fractions idea. But I am on a Mac and not a PC. If it helps others, I have discovered [ctrl][cmd][space] brings up a character map for the Mac and search 'fraction' (singular) gives a few.

Question is, do my two dimensions read correctly on other people's computers? 1⅛", 7½".

Norm

Edited By norm norton on 03/01/2020 15:53:51

On a Mac you load a program called Crossover, and that will run all manner of DOS written code within a specific window. Crossover costs a few pounds (i.e. not much) and although there are free alternatives they require a bit more thought to run. You can get all this information by searching the web. Ask for things like 'run windows programs on Mac' but you do not need a full windows emulator.

Then there are a few valve simulators to download. Although most are Walschaerts I know that the Dockstader has Stephensons. Search for 'walschaerts stephensons valve simulators'.

Edited By norm norton on 19/11/2019 09:47:20

I understand that they are not recommended for 5" gauge in the UK. Speak to an informed club boiler inspector and refer to the boiler code documentation. Sorry I cannot be specific on where to find this.

I am looking for a bigger compressor and I know that I would like a 3HP, belt drive 14cfm with a 100 litre tank. This is the biggest I could run on single phase 13-15 amp and I only want occasional spraying and air tool use.

There are a number of known suppliers (e.g. R-Tec, Thorite, NuAIr) who stock branded compressors to this specification in the £480 - £560 (incl.vat) price band. However there is an equivalent compressor called a Burisch BT390 that is available for £276.

Now that is a lot less money for my intermittent use, but why is it so much cheaper? Is it going to be horribly noisy or will it fail after 12 months? If I ask the suppliers I know what they will tell me, but I would be interested to hear any independent view.

These imperial tables for a 140 were all on the Harrison Yahoo forum site, I am sure I put some there, but it is all shut down now by the recent Yahoo policy. There is a new Harrison site and I will have to see if the files of reference data have been transferred across.

I will post my simple .jpg of information here in the hope that it is readable. If not message me with your email and I will copy it to you.

I have had a good try at searching the web for a few answers on this, but surprisingly few thoughts about what ought to be a common problem. Most seem to put up with it, or complain that British Gas can't fix it, so I will ask for some thoughts here.

When my gas boiler system motorised valve operates any DAB radio drops out for the 12-15 seconds and now the super fibre internet router also trips off and then does its usual power back on. Funnily enough, the TV seems unaffected. The DAB radio drop out has been going on for a few years.

The various web answers point to thermostats, boiler gas valves and motorised valves as being the guilty objects. But no thoughts on suppression given. It cannot be the roomstat (happens in the Summer), I have a newish Worcester Greenstar boiler, but the interference does coincide with the actuation and duration of the motorised valve when the hot water tank thermostat seems to be ending its call for heat.

Apparently there are resistor/capacitor sets in some motorised valves. Do you think I can try putting a capacitor (or pair) across the motor feed cable supply? What size and type and do I affix a L-E and a N-E pair?

Or have I got to dismantle the motor drive and replace any capacitor that might be lurking in there?

It might be the tankstat if that can take 12-15 seconds to trip off, but unlikely perhaps.

Norm

Edited By norm norton on 01/09/2019 12:05:45

quote above : "The Victorian construction of the dam appears to be perfectly sound. It's well over a century old and even with the failure of the spillway it's remained functioning despite taking some very serious damage."

The above is something I agree with, although I am not a dam or construction expert and I have only seen the broadcast pictures. Local residents are saying things like "we were saved from an imminent collapse". Who ever thought it was about to give way? There were no reports of water penetration, which normally precedes a collapse.

Certainly any consulted engineer would have to report that its condition was weaker than before the overspill, and that it might give way if more water came over the top and removed a substantial amount of the soil wall. I suspect that liability and risk management then took over and the various agencies all stated that it was in danger of imminent collapse with the need for evacuation.

It will be interesting if any reports appear from any construction expert regarding how much soil wall had been removed and how much weaker it then was, with the full head of water behind it.

There is/was a small 'sample or trial' kit of eight little tubs (2" dia. x 2" high) that I bought a few years ago.

Norm

Hi Alan

Search for Rocol Steam Seal which is designed for this very job. Suppliers on eBay, and Heritage Steam are a good company.

Norm

Hello Peter

The packing needs to just standing a 'bit' proud, but it will be all over the place with high spots and hollows. Once it is in the bore it should even itself out. Yes you want to be able to 'just' pull and push the piston gripping the piston rod. It will be tight so oil it.

Make a conical adapter (5-10 deg internal taper) that you feed the piston and packing into, then line that up with the cylinder bore to easily slide in. The inside bore of the adapter exit should be the same as the cylinder bore. The taper helps squeeze it all into shape.

Norm

Very rude of us John to find humour in your fine feed numbers and I apologise for starting it. What you have listed is a perfectly logical way of showing the fineness of feed.

But I like that idea that at 569 TPI my Myford Series Seven might do better than the 'world's finest known thread' of 508 TPI. I might have a try, should I sharpen the 60 degree Whitworth tool first?

Yes we all agree that the steam condenses in the lubricator vessel and it is this that displaces the oil. My apologies if I misled by not saying that I agreed with this basic principle at the start.

Our discussion is whether this Simple Displacement Lubricator might be a continuous system or a cyclic one. This lubricator uses the same entrance and exit to the steam line, or steam chest as fitted by Stuart. I suggest that the flow direction must cycle. An experiment would be simple to do - just connect a steam line to it and leave it under pressure, and see if it gradually fills with water and all the oil transfers to the steam line.

There is another configuration sometimes called the Hydrostatic or Ramsbottom style that has a steam inlet, typically from the regulator supply, to the displacement vessel and a separate oil outlet to the cylinders. These do not need to cycle and are effectively continuous. They were developed for use on full size steam locomotives and even included sight glasses to observe the dripping oil flow. If configured to take some steam directly from the boiler they would then operate continuously. They are still used on some model locomotives, especially GWR variants.

Every respect Duncan, but your version makes less sense. You suggest that steam keeps flowing through the pipe, and any small jet or valve, at the same time as oil flows the other way? Which end of the pipe has the higher pressure? A cyclic system however will follow the inevitable pressure changes in the steam supply. A small bubble of air is necessary to allow that cycle to execute and balance the pressure in the reservoir to that in the steam line.

I love the last line in the chart showing what you need for 569 TPI (!!!) Can't think of an immediate use for that..

Out of interest, what is the finest thread used on a practical object that is known of?

Norm

The steam enters the oil chamber and condenses only when there has been a change in pressure, i.e. you start the engine. Then when the pressure drops some oil will be expelled into the steam line. If running at constant speed there will be no additional oil introduced. The volume of oil displaced each cycle also depends on the amount of (compressible) air in the reservoir at the start.

It just needs a reasonable one inch or more of small bore tube to tee off the steam line and possibly a jet of 0.010" or 0.020" in the line if it does empty the oil too quickly.

Well said Russell. I completely forgot that. I use the same all the time - essential on the taps.

For small drills of this size I have never found that adding anything wet helps. Lubricant starts to work when things are getting hot.

As Jason has said, once the hole is drilled then use the chuck to help line up the tap. For 10 BA and smaller grip the tap with a small Pin Vice, not a Tee Holder, and just use finger and thumb to rotate and sense the resistance. Don't grip the Pin Vice in the chuck, just use a pointed rod to visually align things. One finger on top of the Pin Vice to get it to bite and descend. Take it out every turn and brush off the swarf.

For bigger jobs a spring centering tool can be held in the chuck, but I don't find one helpful with tiny taps, and the tops don't have locating holes anyway. If you have not got a Pin Vice then look for some genuine used Eclipse ones on eBay. Don't buy cheapie £10 new sets as they won't grip and will be off-centre.